1. Field of the Invention
The present invention relates to a calibration apparatus and a calibration method for calibrating an electronic device such as a semiconductor device and to a testing apparatus and a testing method for testing the electronic device. More specifically, the invention relates to an apparatus and a method for calibrating an electronic device having a demodulator.
2. Related Art
Conventionally, the following two methods have been known as methods for evaluating a signal-under-measurement generated within an electronic device such as an output signal of the electronic device and a signal transmitting among circuits within the electronic device.
The first method is a method of evaluating the signal-under-measurement by taking it out of the electronic device and the second method is a method of evaluating it within the electronic device by using BIST (Built-In Self-Test).
However, if frequency of the signal-under-measurement is high in evaluating the signal-under-measurement by the first method, the signal-under-measurement deteriorates due to LC components and transmission paths of a package of the electronic device.
Therefore, there is a case of excessively evaluating modulated components (or a quantity of jitter) of the signal-under-measurement for example in measuring it by this method as compared to the case of measuring it within the electronic device. Therefore, it is unable to accurately measure the signal-under-measurement by this method.
Still more, frequency characteristics of the BIST circuit varies due to fluctuations of semiconductor manufacturing process and to changes of temperature, supplied voltage and the like in evaluating the signal-under-measurement by the second method.
The electronic devices also vary among each other. Therefore, it is necessary to measure the frequency characteristics of the BIST circuit and to calibrate it per electronic device in order to accurately measure the signal-under-measurement. For example, it is necessary to measure a gain in the BIST circuit per frequency.
Therefore, it is difficult to use this method in a mass-production test that requires to conduct a test in a short time.
Accordingly, it is an object of the invention to provide a calibration apparatus, a calibration method, a testing apparatus and a testing method, which are capable of solving the above-mentioned problems.
This object may be achieved through the combination of features described in independent claims of the invention. Dependent claims thereof specify preferable embodiments of the invention.